Mobile billboard



FIG. 1 is a top plan view of my new design for a mobile billboard, the bottom plan view is a mirror image;

FIG. 2 is a front elevational view thereof, the rear view has no design features;

FIG. 3 is a right side elevational view thereof, the left side is a mirror image; and,

FIG. 4 is a front elevational view of a modified form showing a second embodiment of FIG. 2. 

The ornamental design for a mobile billboard, as shown and described. 